Power door operator



June 3, 1941. c. J. MARTIN ETAL POWER DOOR OPERATOR Filed Sept. 30, 1939 2 Sheets-Sheet l I/vmv T058. 11": i- Wt: 95 5 A TTO NE Y5 June 1941- c. J. MARTIN ETAL 2,243,914

POWER DOOR OPERATOR Filed Sept. 30, 1939 2 Sheets-Sheet 2 INVENTOHS. Curfis J. Mari-in Seph F- asKa 6L ATT RNEY V Patented June 3, 1941 POWER DOOR OPERATOR Curtis J. Martin, Chicago, and Joseph F. Maska, Cicero, 11L, assignors to ltlationalv Pneumatic Company, New York, N. Y., a corporation of West Virginia Application September 30, 1939, Serial No. 297,214

3 Claims.

This invention relates to improvements in power operated doors of all kinds in which an important feature embodies the idea of a motive device connected to the door and controls therefor whereby the motive device is acting at all times to move the door to open position, the door being held latched closed so that as soon as it is unlatched the motor immediately opens the door.

The many objects of this invention will be apparent from the following detailed disclosure thereof when taken in connection with the attached drawings.

This invention resides substantially in the combination, construction, arrangement and relative location of parts, all in accordance with this disclosure.

In the accompanying drawings,

Figure l is a top plan view of a portion of a door showing the motor device mounted above it and attached to the door to operate it;

Figure 2 is a diagrammatic view showing thev a modified form with arrangements so that as soon as the door is unlatched a motor device automatically operates to open the door, eliminating the necessity of manual operation thereof. One example of the utility of such an arrangement is in the case of vehicles, such as, for example, railway cars, where passengers frequently desire to open the end doors of the vehicle while it is decelerating.

Under these conditions the weight of the door,

plus the inertia thereof due to the deceleration of the vehicle and the resistance offered by the door check which is frequently used, all require a force to overcome them in opening the door which is undesirably large for manual operation. In such cases the invention herein disclosed is particularly efiective.

As illustrated in Figure 1, the door opening in the end of a railway car, for example, is formed by a framing, a portion of which is indicated at 4. Mounted in the door opening is the usual swinging door I, which is supported by means of suitable hinges 3. Secured over the door opening is a plate or bracket 5 or even the member forming the top of the opening on which the motive device is mounted. In the form of the invention herein'disclosed, this motive device is illustrated as of the differential pressure fluid operated type. This engine is secured adjacent the door opening by means of a bracket 6 and comprises, as is usual in the case of a difierential pressure operated engine, a large cylinder 1 and a smaller cylinder 8 mounted in alignment. Within these'cylinders are two pistons of different sizes which are connected together. The space between the pistons is constantly supplied with pressure fluid through a pipe connected to the port 9. The right hand end of cylinder 8 is provided with a casing l0 which is normally ported so that the right hand face of the smaller piston is always open to the atmosphere and is provided with a rack extension which projects into the casing 10 in accordance with common practice. This rack engages a pinion mounted on a shaft ll supported in the housing 10 for rotation on a vertical axis. Thus the linear movements of the piston is converted into rotary movement. Such a construction is well known, and for this reason the details of the rack and pinion and mounting of shaft II are not illustrated.

Secured to the shaft II and extending horizontally above the door opening is an arm 12 which is pivotally connected at l3 to a link M. This link in turn is pivotally connected to a horizontal pivot pin 15 in a coupling II which in turn is pivoted on the vertical pivot pin iii to a bracket 16 which is secured to the door I in any suitable manner.

As will appear later the piston assembly is at the right hand end of its stroke, that is, the respective pistons are at the right hand ends of cylinders I and 8 when the door is closed, at which time the rack is fully projected into the housing l0. At this time the left hand end of the large cylinder is open to exhaust and the pressure fluid supplied between the pistons has caused them to take this position. The door is latched closed and as soon as it is unlatched thepressure acting between the pistons causedthem to move to the left, retracting the-rack and causing arm l2 to rotate in a clockwise direction. Thus the door I opens by swinging upwardly with respect to Figure 1. The circuit arrangements for accomplishing thisoperationwill now be described in connection with Figure 2.

The differential engine is shown at 1-8, and the operating lever at I 2. At I9 is a pipe extending from any suitable source of pressure fluid to a control valve 20 which will normally be open when the apparatus is in use. This valve is connected by pipe 22 to a needle valve 23, which in turn is connected to the port 9. A strainer of any suitable construction is shown diagrammatically at 2| in the pipe connection to remove the moisture and foreign material, as is very common in this field.

A branch pipe 24 extends from the pipe 22 to the feed connection of a valve 25 which is operated by a solenoid 28. This combination comprises a pressure type electromagnet valve of a very common and well known type, the full details of which are shown in Figure 38 of U. S. Patent 1,849,516. When the winding 28 is deenergized, valve 25 is closed so that pressure fluid is confined to the branch 24. A pipe connection 26 with the two contacts connected to the wire 3| and one terminal of winding 28. Aparallel path or holding circuit for' winding 38 i then com- .pleted to wire 3|, through contact 34, wire 35, switch 36 which is now closed, wire 31, normally closed switch 38, wire 42, and wire 33 to ground. The winding 28 is also energized from wire 29, through the lower contact of the relay and the same circuit comprising the holding circuit for winding 38.

Thus valve 25 is operated to connect pipe 24 to pipe 26, with the result that pressure fluid flows into the left end of cylinder 1 moving the piston extends from the valve 25 to another needle valve 21, which in turn is connected to the of large cylinder 25.

A wire 23 extends from the positive side of a suitable current source to one terminal of the operating winding of a relay 38. The other terminal of this winding is connected by wire 3|, through a switch 32 which is normally open, and by wire 33 to ground. The movable contact 34 of the relay 38 is connected by a. wire 35 through a normally open switch 36, wire 31, normally closed switch 38, and wire 42 to wire 33. The switch 36 is mounted in the door frame adjacent the latch 5|. The latch 5| is operated by the usual handle or knob 58 forming part of the look, all of which are mounted on the door in the usual manner so the latch engages a latch plate on the door jamb. When the door is latched closed the latch 5| holds switch 36 open. As soon as the door is unlatched a spring closes switch 36, in accordance with well known practice. At 4| is shown a portion of-one of the panels of the door I which is provided with a plate or other suitable form of operator 39 on the outer face, that is, the vestibule side in the case of a vehicle, and is connected with switch 38 so that it is open when plate 39 is pressed. A handie-48 on the other side of the door panel is provided to operate switch 38 when desired. Switch 38 is normally closed and can be held closed with a spring in accordance with well known practice. Switch 32 is normally held open with a spring in accordance with common practice.

In describing the operation of this system,.it will be assumed that the door is closed. At this time winding 28 of the magnet is deenergized so that the left hand end of cylinder I is open to the atmosphere through needle valve 21, connection 25, and the exhaust port of valve 25. At this time the door is closed and held closed by latch 5|. The piston assembly in the cylindare I and 8 is at the right hand and and pressure fluid is constantlvsupplied between them through the port 9. When a person desires to open the door he simply turns the knob 58 which withdraws the latch 5|, unlatching the door. Immediately switch 35 closes, but no circuits are completed because the relay 38 is deenergized. Since the left hand end of cylinder 1 is open to exhaust and the pressure acting on the inner faces of the large and small pistons is unbalanced towards the left, the piston assembly immediately moves to the left, opening the door.

Just as the door fully opens, it engages switch 32 and closes it. The result is that current flows through wire 29, winding 38, wire 3|, switch 32 a and wire 33 to ground. The energization of winding 38 moves contact 34 into engagement assembly towards the right and causing the door to close. As soon as it begins to close, switch 32 opens but the circuit for windings 28 and 38 is maintained through switches 36 and 38. Thus the piston assembly continues to move until the door is fully closed and just as it latches shut switch 36 opens, with the result that the holding circuit for magnet 38 is broken and contact 34 disengages its contacts. At the same time, of course, the winding 28 is deenergized and valve 25 moves back to disconnect pipe 24 from pipe 26 and connect pipe 26 with exhaust. Thus the pressure in the left hand end of cylinder 1 immediately exhausts to the atmosphere. Further, the piston assembly cannot move back because the door is latched shut. If during the closing movement of the door it is desired for any reason to cause it to return to fully open position,

switch 38 is opened either by the plate 39 or the handle 48. This breaks the holding circuit for windings 28 and 38 and the left hand end of cylinder 1 is open to exhaust so that the engine again opens the door until switch 32 is closed, at which time the closing operations previously described again occur.

The system of Figure 3 differs in the general respect that the engine and controlling appararatus is not so conditioned that when the door is closed it is necessary that it be latched to hold it closed. In other words, with this arrangement the engine is so energized that it holds the door closed. The arrangement of Figure 3 diflers from that of Figure 2 in that the electromagnet valve 25 in Figure 3 is of the exhaust type, as illustrated in full detail, for example, in Figure 37 of Patent No. 1,849,516, mentioned above. Thus the connection 26 in Figure 3 is open to the atmosphere and cut oil from the supply of pressure fluid when the winding 28 of the magnet valve is energized, as distinguished from the arrangement in Figure 2 where when the winding 28 is energized the pipe 26 is connected to the pressure fluid source and, of course, cut off from exhaust. In each system the engine pistons move to the left to open the door. As explained above, in the arrangement of Figure 2, the pressure fluid is exhausted from the left hand end of the large cylinder when the door is fully open. In the arrangement of Figure 3, however, fluid pressure is on both the large and small cylinders when the door is closed, tending to hold it closed, and the air must be exhausted from the left hand end of the large engine to open the door. ,In this case the door latch is not essential except in so far as door latches are generally desirable. A more detailed description of the operation of the system of Figure 3 follows. V

In this case it will be noted that the return connection from the winding 28 goes to a contact which is engaged by the movable contact 34 when winding 38 is deenergized. Otherwise the connections are the same as those of Figure 2 with the exception that the reversing switch 38 has been omitted, although it could be used if desired. In the operation of this system, in order to open a door, a person turns the knob 50, withdrawing latch so that switch 36 closes. Current then flows from wire 29, through winding 28, switch 34, wire 35, switch 36, wire 31, and wire 33 to ground. Valve 25 is operated to connect pipe 24 to pipe 26, with the result that the piston assembly moves to the left, opening the door. Just as the door fully opens, it engages switch 32 to close it. This completes a circuit from wire 29 through winding 3i], wire 3i, switch 32, and wire 33 to ground; Switch M then moves to its other position, completing a holding circuit for the winding 30, through switch 36, and breaking the circuit to the winding 28. As a result of the deenergization of winding 28, valve 25 connects pipe 28 to pipe 26 and disconnects pipe 26 from exhaust. The constant pressure through port 9 on the difierential pistons then causes them to move back to the right, closing the door. As soon as the door begins to close, switch 32 opens, but no other operation results because of the holding circuit through switch 36. However, as the door latches shut, switch 36 is opened, breaking the holding circuit so that switch 34 returns to the position shown in Figure 3 and the apparatus is ready for its next operation. It is, of course, apparent to those skilled in the art that switch 38 could be included in the wire 31 to perform the reversing function described in connection with Figure 2.

In all of the arrangements the needle valves 23 and 21 are merely supplied for the purpose of controlling the speed of the operation of the engine in either direction, all in accordance with very common practice in this art.

From the above description it will be apparent to those skilled in the art that this invention may be embodied in other physical forms without departing from the objects and functions thereof. We do not, therefore, desire to be strictly limited to the disclosure as given for purposes of illustration but rather to the scope of the claims granted us.

What we claim is:

1. A combination as described, comprising a door, a difierential pneumatic engine mounted adjacent the door and connected to it, the said engine having a differential piston assembly, a pressure fluid connection to said engine to continuously supply pressure fluid to the space between the piston assembly, electromagnetic means when energized for supplying pressure fluid to the large cylinder of the differential engine and to exhaust it therefrom when deenergized, a latch on said door for latching it closed, and circuit connections for said electromagnetic valve including a plurality of switches, one normally held open by the latch when the door is latched closed, another normally open andpositioned to be closed when the door is fully open, and another closed when said last switch is closed, whereby as soon as the door is unlatched the engine opens it and when it reaches fully open position it closes the switch operated thereby to close said third switch to energize said magnet valve so that pressure fluid is supplied to the engine to close the door and the latch opens said first switch when the door is fully closed to open said third switch.

2. A combination as described, including a door, a differential engine having a differential piston assembly connected to thedoor, a pressure fluid supply connection to the space formed by the piston assembly for continuously supplying pressure fluid thereto, a latch for locking the door closed, said piston assembly when the door is closed being so positioned that it tends to move to another position whereby as soon as the door is unlatched the engine opens it, and fluid pressure supply and exhaust control means cooperating with said door to supply pressure fluid to said engine from said supply connection as the door reaches open position to move the piston assembly in the reverse direction to close the door and to vent said engine when the door is latched in closed position.

3. In a door operating system, the combination including a door, a diflerential fluid pressure engine connected to said door to open and close it, said engine having a pair of connected pistons and cylinders of different diameters, a latch for holding the door in closed position, means for continuously supplying pressure fluid to the engine between said pistons so that the engine tends to move the door to open position when the large cylinder is open to exhaust, a pressure fluid control means for controlling the fluid supply and exhaust for said large cylinder, said fluidcontrol means being in a position to exhaust the large cylinder whenever the door is closed and a door operated control device for said control means whereby said engine opens the door when the latch is operated to release the door and said door operates the control device to actuate said control means to cut off the exhaust and establish the fluid supply of said large cylinder to close the door.

CURTIS J. MARTIN. JOSEPH F. MASKA. 

